Category: Renewable energy

Grids, Smart Grids and More Grids: What’s Coming

In an earlier blog post on energy storage I stated that there are two developments related to the widespread use of renewable energy that ‘I would fall on my sword for’, energy storage and smart grids. This post discusses the second of these in the context of large-scale smart grids and smaller minigrids. Both are critical to the future of renewable energy in both developed and developing countries.

Grids are collections of wires,switches,transformers,substations, and related equipment that enables the delivery of electrical energy from a generator to a consumer of that energy. A traditional grid structure today is shown below:

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The first grid, for delivery of alternating current (AC) electricity, was put into operation in 1886. Electrical energy can be delivered as either AC or DC (direct current) electricity, but for over a century AC has been the preferred delivery mechanism. A more complete discussion of AC vs. DC is a good topic for a future blog post.

The traditional grid is a one-way distribution network that delivers power from large centralized generating stations to customers via a radial network of wires. Regional grids, when integrated, constitute a national grid, something the historically balkanized U.S. electric utility system is still trying to achieve. Transmission lines are long distance carriers of electrical energy transmitted at high voltages and low currents to minimize electrical losses due to heating in wires. This high voltage energy is then reduced via transformers to lower voltage, usually 120 or 240 volts, to supply local distribution networks that bring the energy to our homes and businesses. The U.S. Energy Information Administration estimates that national electricity transmission and distribution (T&D) losses average about 6% of the electricity that is transmitted and distributed in the United States each year.

While the traditional grid has brought the benefits of electricity to billions of people for many decades, its shortcomings have become more visible in recent years. The problem is its vulnerability to disruption by extreme weather events (only a small fraction of T&D wires are underground), physical attack and accidents leading to widespread power outages, cyber attack in today’s world of increasing dependence on information technologies, and even large solar storms that strike the earth occasionally and interact with the T&D system acting as giant antennas.

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The utility industry has usually (but not always) resisted putting wires underground because of high costs, and increased effort is going into trimming trees that can fall on or otherwise disrupt power lines. Control of the grid has also been improved to minimize the possibility of disruption in one grid sector spreading to others, but this is a costly work in progress. What is looming as a major threat to the traditional grid is its increasing dependence on automated remote control via advanced computer/information technologies built into the grid system that are vulnerable to hacking and other malevolent interventions.

Grid systems with computer controls are referred to as smart grids. Through the gathering, communication, analysis, and application of analog or digital information on the behavior of suppliers and consumers, a smart grid can use automation “..to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity.” The issue of cyber vulnerability has only begun to receive careful attention in recent years as the hacking phenomenon has surged and the ability to interrupt remote industrial activities via computer viruses such as Stuxnet have been demonstrated.

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What can be done to protect against this vulnerability? Considerable effort is going into developing software that is resistant to hacking, but this is proving extremely difficult to achieve. As has become all too obvious, there are lots of talented hackers out there and some of them are supported by national governments. Nevertheless, this is a path that has to be pursued, and is becoming a priority in the training of new IT programmers and specialists.

Another approach is to move away from the historic centralized grid and move to a grid system where disturbances can be isolated (islanded) once detected and thus unable to affect other parts of the grid. This will require distributed generation sources that supply unaffected parts of the grid, and could be other centralized generators that can be tapped or local renewable energy sources (wind, solar) that are not in the disturbed grid sector.

Traditional grids are expensive, and extending these grids from urban to remote areas often can not be justified economically. This is particularly true in developing countries where most of the world’s 1.5 billion people without access to electricity reside. Improving access to modern energy services in rural areas is a major development priority, and there is increasing attention to decentralized generation and distribution through mini-grids. “A ‘mini-grid’ is an isolated, low-voltage distribution grid, providing electricity to a community – typically a village or very small town. It is normally supplied by one source of electricity, e.g. diesel generators, a solar PV installation, a micro-hydro station, etc., or a combination of the above.” It includes control capability, which means it can disconnect from a traditional grid and operate autonomously.

A recent workshop organized by the Africa-EU Renewable Energy Cooperation Programme (RECP), held in Tanzania in September 2013, focused on this rapidly emerging option – ‘Mini-Grids: Opportunities for Rural development in Africa’. The workshop background was described as follows: “Given Africa’s abundance of renewable energy resources, the widespread existence of isolated, expensive, highly-subsidized fossil-fuel based mini-grids on the continent, very low grid connection rates, the often low levels of electricity demand from households, the high costs associated with grid extension, the lack of reliable, centralized generation capacity and increasing levels of densification as a result of ongoing urbanization, renewable energy and hybrid-based mini-grids provide a practical, efficient energy access solution.” It should also be noted that the use of renewables can reduce fossil-fuel use, reduce carbon emissions, and create local jobs and economic development.

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Another type of mini-grid is the micro-grid, a term used to describe mini-grids that deliver DC electricity to its consumers. Still another variation is the skinny-grid, which emphasizes the use of energy efficiency technologies to reduce consumer demand and thus allow the use of thinner and less expensive connecting wires between generators and end users.

I will conclude this blog post by discussing the role of smart grids in facilitating the integration of renewable energy into the grid. Renewable energy is now growing rapidly as a share of the global energy mix and this trend will continue as we move further into the 21st century. We are also learning that, despite the variable nature of solar and wind energy, by using the control features of increasingly sophisticated smart grids and the use of energy storage, this integration can be done safely and cost effectively with high levels of renewables penetration.

IRENA, the International Renewable Energy Agency headquartered in Abu Dhabi, has addressed this issue in a comprehensive November 2013 report entitled ‘Smart Grids and Renewables’. As stated in the Executive Summary: “This report is intended as a pragmatic user’s guide on how to make optimal use of smart grid technologies for the integration of renewables into the grid. …The report also provides a detailed review of smart grid technologies for renewables, including their costs, technical status, applicability and market maturity for various uses.” It acknowledges that “Much of what is known or discussed about smart grids and renewables in the literature is still at the conceptual/visionary stage..” but includes “..several case studies that involve actual, real-world installation and use of smart-grid technologies that enable renewables.” The report also points to needed policy and regulatory changes for successful renewables integration. It is a valuable and forward-looking document.

A Personal View

The attached article entitled ‘Why the U.S. has not made more progress in moving toward a renewable energy future – a personal view’ was published on June 30, 2014 in the ejournal energy post (www.energypost.eu). My reason for writing this piece is explained in the text. It expands on an earlier blog post by adding, in some detail, my personal answer to the question raised in the article’s title.

Why the U.S. has not made more progress in moving toward a renewable energy future – a personal view
June 30, 2014 – Author: Allan Hoffman

Editor’s note: In 1978 a monumental multi-departmental study was submitted to President Carter concluding that “solar energy could make a significant contribution to U.S. energy supply by the end of this century”. The study, backed by 30 federal departments, stated that “even with today’s subsidized energy prices, many solar technologies are already economic.” Yet no action was taken and solar power and other renewable energies stagnated for over 30 years. Until now? Allan Hoffman, former senior official at the U.S. Department of Energy, who personally delivered the report to the White House back in 1978, recalls what went wrong – and what lessons the U.S. should draw if it is to avoid another failed renewables revolution.
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On December 6, 1978 I personally delivered a multi-agency report to the staff of the Domestic Policy Advisor to President Carter entitled ‘Domestic Policy Review of Solar Energy: A Response Memorandum to The President of the United States’. It is popularly known as the DPR. The report had been requested by the President in a May 3, 1978 speech in Golden, Colorado, dedicating the newly formed Solar Energy Research Institute (SERI). SERI has since become the National Renewable Energy Laboratory (NREL).

The DPR was the final report of the first comprehensive review by the U.S. federal government of its policies for renewable energy. It involved 30 federal departments and agencies, and at its peak this 6-month study involved the efforts of 175 senior government officials detailed to the DPR task force. As the U.S. Department of Energy’s senior representative to the DPR, and just one month after I had joined DOE as a political appointee, I was designated to head the effort by my new boss, the head of DOE’s Policy Office.

My hopes were dashed when President Clinton tried to put a price on carbon by raising gasoline prices by five cents a gallon and ran into a political firestorm. He never tried again.
The next six months were rather intense, starting with the fact that the other 29 departments and agencies didn’t trust the 30th, DOE, because of some recent history. Shortly before the DPR was announced the Carter Administration had released a National Energy Policy, also a multi-agency effort chaired by DOE. The story I was told by non-DOE staff was that DOE, at the last minute, had pulled out a draft it had prepared on its own and submitted it as the multi-agency report. As a result I inherited a problem of trust and spent much of the DPR’s first month building relationships with the non-DOE detailees to reestablish that trust. The DPR was completed in early December 1978, and delivered to the White House shortly thereafter. The full report, with appendices, was formally published in February 1979 and is available in DOE’s archives.

Point well taken
The reason I am writing about it now is that my wife recently happened to read it for the first time, and had a ‘strong’ reaction. She asked me, quite forcefully, WTF has it taken the U.S. so long to implement what we recommended more than 35 years ago? Point well taken! She also recommended that I write about this failure and “name names”. As a government retiree (as of September 30, 2012) I feel free to do that without constraint, recognizing that others may have different views on the subject. In fact, I will let the readers of this piece make up their own minds by reproducing the seven-page Executive Summary in full below before offering my views. It also serves as a piece of history that most people today are not familiar with.

Here it is.

“Domestic Policy Review of Solar Energy: A Response Memorandum to The President of the United States
(February 1979, TID-22834/Dist. Category UC-13)

EXECUTIVE SUMMARY

INTRODUCTION

In your May 3, 1978, Sun Day speech, you called for a Domestic Policy Review (DPR) of solar energy. Stuart Eizenstat followed on May 16 with a memorandum defining its scope to include:

A thorough review of the current Federal solar programs to determine whether they, taken as a whole, represent an optimal program for bringing solar technologies into widespread commercial use on an accelerated timetable;
A sound analysis of the contribution which solar energy can make to U.S. and international energy demand, both in the short and longer term;
Recommendations for an overall solar strbategy to pull together Federal, State and private efforts to accelerate the use of solar technologies.

In response to this memorandum, an interagency Solar Energy Policy Committee under the chairmanship of the Secretary of Energy was formed to conduct the review. Over 100 officials representing more than 30 executive departments and agencies have participated since early June.

This review was conducted with significant public participation. Twelve regional public forums were convened throughout the Nation during June and July to receive public comments and recommendations on the development of national solar energy policy. The response of the public was impressive, and reflected the growing support for solar energy identified by several recent opinion polls. Several thousand people attended the meetings and over 2000 individuals and organizations submitted oral or written comments.

In addition, briefings were given to members of the Domestic Policy Review by representatives of solar advocacy groups, small businesses, state and local government, public interest and consumer groups, utilities, the energy industry and solar equipment manufacturers. This public input was an important part of the Review.

In large part, themes reflected in the public comments are consistent with the findings of the DPR and the premises of the National Energy Plan. These premises include an emphasis on conservation as a cornerstone of national energy policy, awareness that energy prices should generally reflect the true replacement cost of energy, and recognition of the need to prepare for an orderly transition to an economy based on renewable energy resources. The public forum comments also reflected a deep concern that the poor and the elderly have access to affordable energy.

SUMMARY OF MAJOR FINDINGS

The results of the Domestic Policy Review can be summarized in nine major findings.

1. With appropriate private and government support, solar energy could make a significant contribution to U.S. energy supply by the end of this century. Renewable energy sources, principally biomass and hydropower, now contribute about 4.8 quads or six percent to the U.S. energy supply. Since estimates of future energy supply and demand are imprecise, three generic forecasts of possible solar use were developed. They can be distinguished most readily by the level of effort that would be required to reach them. In the Base Case, where present policies and programs continue, solar energy could displace 10-12 of a total of 95-114 quads in the year 2000 if energy prices rise to the equivalent of $25-32 per barrel of oil in 1977 dollars. A Maximum Practical effort by Federal, state and local governments could result in solar energy displacing 18 quads of conventional energy by the end of the century. Thus, if one assumes the higher future oil price scenario and this Maximum Practical effort, solar could provide about 20 percent of the nation’s energy by the year 2000. The Technical Limit of solar penetration by the year 2000, imposed primarily by the rates at which changes can be made to existing stocks of buildings and equipment, and rates at which solar techniques can be manufactured and deployed, appears to be 25-30 quads.

2. Solar energy offers numerous important advantages over competing technologies. It provides the Nation with a renewable energy source which can have far fewer detrimental environmental effects than conventional sources. To the extent that increased use of solar energy can eventually reduce U.S. dependence on expensive oil imports, it can also improve our balance of payments, alleviate associated economic problems, and contribute to national security. Widespread use of solar energy can also add diversity and flexibility to the nation’s energy supply, providing insurance against the effects of substantial energy price increases or breakdowns in other major energy systems. If oil supplies are sharply curtailed or environmental problems associated with fossil and nuclear fuels cannot be surmounted, solar systems could help reduce the possibility of major economic disruption.

In addition, because solar systems can be matched to many end-uses more effectively than centralized systems, their use can help reduce a large amount of energy waste. Although the U.S. now consumes about 76 quads of energy a year, less than 43 quads actually are used to provide energy directly in useable form. The rest in consumed in conversion, transmission and end-use losses.

3. Even with today’s subsidized energy prices, many solar technologies are already economic and can be used in a wide range of applications. Direct burning of wood has been economic in the private sector for some time, accounting for 1.3 to 1.8 quads of energy use. Combustion of solid wastes or fuels derived from solid wastes is planned for several U.S. cities. Passive solar design can significantly reduce energy use in many structures with little or no increase in building cost. Low head hydroelectric generation is currently economic at favorable sites. Solar hot water systems can compete successfully in many regions against electric resistance heating, and will compete against systems using natural gas in the future. A number of solar systems installed by individual users are cost-effective at today’s market prices. In addition, other solar technologies will become economic with further research, demonstration, and market development, and if subsidies to competing fuels are reduced or removed.

4. Limited public awareness of and confidence in solar technologies is a major barrier to accelerated solar energy use. Public testimony continually emphasized the need for more and better solar information. New programs to educate designers, builders, and potential solar users in the residential, commercial and industrial sectors are needed. Because consumers lack information, they often do not have confidence in solar products. Programs to provide reliable information to consumers, to protect them from defects in the manufacture and installation of solar equipment, and to assure competition in the solar industry can help build consumer confidence in the future.

5. Widespread use of solar energy is also hindered by Federal and state policies and market imperfections that effectively subsidize competing energy sources. These policies include Federal price controls on oil, and gas, a wide variety of direct and indirect subsidies, and utility rate structures that are based on average, rather than marginal costs. Also, the market system fails to reflect the full social benefits and costs of competing energy sources, such as the costs of air and water pollution. If solar energy were given economic parity with conventional fuels through the removal of these subsidies, its market position would be enhanced.

6. Financial barriers faced by users and small producers are among the most serious obstacles to increased solar energy use. Most solar technologies cannot compete effectively with conventional fuels at current market prices, in part because of subsidies, price controls, and average-cost utility rate structures for these conventional fuels. The tax credit provisions in the National Energy Act (NEA) will improve the economics of certain solar technologies, particularly in the residential sector.

Other barriers exist because the high initial costs of solar systems often cannot be spread over their useful lives. Industry and consumers have yet to develop experience in financing and marketing solar systems. Some of the provisions of the National Energy Act will help expand credit for residential/commercial solar systems. In addition, the new Small Business Energy Loan Act will provide credit assistance to small solar industry firms. Other existing Federal financial programs, which were created for other purposes, could also help finance solar purchases if they were directed toward this end.

7. Although the current Federal solar research, development and demonstration (RD&D) program is substantial, government funding priorities should be linked more closely with national energy goals. Solar RD&D budgets, which have totaled about $1.5 billion in the Fiscal Year (FY) 1974 to FY 1979 period, have not adequately concentrated on systems that have near-term applications and can help displace oil and gas. Electricity from large, centralized technologies has been over-emphasized while near-term technologies for the direct production of heat and fuels, community-scale applications and low-cost systems have not received adequate support. Basic research on advanced solar concepts has also been under-emphasized, limiting the long-term contribution of solar energy to the nation’s energy supply.

8. Solar energy presents the U.S. with an important opportunity to advance its foreign policy and international trade objectives. The United States can demonstrate international leadership by cooperating with other countries in the development of solar technologies, and by assisting developing nations with solar applications. Use of decentralized solar energy can be an important component of development planning in less developed counties which do not have extensive power grids, and cannot afford expensive energy supply systems. In many cases, solar may be the only energy source practically available to improve rural living conditions. Through such efforts, the U.S. could also help to develop new foreign markets for U.S. products and services, thereby increasing opportunities for employment in solar and related industries at home. And, as solar energy eventually begins to displace imported oil and natural gas, the U.S. will enjoy greater flexibility in the conduct of its foreign policy. Insofar as solar energy systems reduce the need for nuclear and petroleum fuels in the long-term, they can help reduce the risk of nuclear proliferation and international tensions arising from competition for increasingly scarce fossil fuels.

9. Although the Federal government can provide a leadership role, Federal actions alone cannot ensure wide-spread use. Many barriers to the use of solar energy, and opportunities to accelerate its use, occur at state and local levels. In order to overcome these barriers and take advantage of these opportunities, a concentrated effort at all levels of government and by large segments of the public will be required. Nevertheless, the Federal government can set a pattern of leadership and create a climate conducive to private development and use of solar energy in a competitive market. These efforts must also recognize the wide variation among solar technologies and the resulting need to tailor initiatives to specific solar applications.”

This was 35 years ago and in hindsight it is clear that the powerful recommendations in our study were largely ignored. We thereby missed a great opportunity to transform our society in a way that would have enabled us to avoid many of the traumatic geopolitical, economic and environmental problems we faced in the ensuing years.

Why? Allow me to offer some personal reflections on this. My views take issue with both political parties and with vested interests in traditional energy industries. They are based on my experiences over nearly forty years in Washington, including service as Staff Scientist for the Senate Committee on Commerce, Science and Transportation, and many years as a senior official at the U.S. Department of Energy. Let me start with President Carter.

I served in the Carter Administration for nineteen months as head of the renewable energy policy division in the newly established Department of Energy. The DPR was my primary responsibility during that time and was received by a President who was favorably disposed towards renewable energy technologies. In fact he installed solar hot water heating panels on the White House roof and used the DPR as the basis of his dedication speech in April 1979.

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President Carter installs solar power at White House
(Photo: AP/Harvey George)

Where I take issue with his promotion of renewable energy is in his denial of a requested increase in the R&D budget for renewables, arguing that we had to balance the FY1981 budget. I accepted his argument at the time but rejected it later when the President somehow found $88 billion for a new synfuels program, probably motivated by his then poor standings in the polls. I was sufficiently upset by this development that I left DOE shortly thereafter.

Of course President Carter lost to Ronald Reagan in the 1980 presidential election and the following eight years were terrible for renewable energy, and for DOE in general. President Reagan and his aides set out to eliminate two Federal Departments – DOE1 (Energy) and DOE2 (Education), but succeeded in neither. Nevertheless, they did remove the solar panels from the White House roof and serious damage was done in those years to the renewable energy budget – it was reduced by a factor of eight! Only the determined efforts of a few dedicated DOE managers (particularly Bob San Martin, the head of the renewable electric programs) kept the programs alive. It was also during this period that oil prices took a dive to below $10 a barrel and public interest in alternative energy was diminished significantly.

Things improved in the four years under George Bush Sr. – budgets edged up slightly and SERI was designated as a National Laboratory, NREL. The 1992 election also saw Bill Clinton elected as President and Al Gore as Vice President, and hopes were high that renewable energy R&D budgets would increase. I was now back at DOE helping to run the renewable energy programs, first as Associate Deputy Assistant Secretary, and then as Acting Deputy Assistant Secretary for more than three years. While annual budgets did increase somewhat to about $300 million, I knew that this was less than required for a fully effective program (the budget covered solar, wind, hydropower, geothermal, biomass, ocean energy, energy storage, and superconductivity), which I estimated to be $450 million.

Political firestorm
Not expecting much action in a first Clinton term (there were lots of other ‘fish to fry’) I looked forward to Clinton’s second term. Of course my hopes were dashed when the President tried to put a price on carbon by raising gasoline prices by five cents a gallon and ran into a political firestorm. He never tried again. Vice President Gore was also responsible for a serious setback when he insisted that all programs aimed at reducing global warming be so labeled in the FY1996 budget request, which many of us argued against strongly.

We were unsuccessful, the Republicans won both the House and Senate in that off-year election, and the Gingrich Revolution that followed used the Gore budget identifications as a guide to reducing the renewable energy budget by 25%. This had serious consequences for NREL, which received 60 % of its operating funds from that budget, and NREL was forced to lay off 200 of its 800 staff. It was a devastating time for renewables, about which I still carry strong feelings. One of those feelings is that we had a President and Vice President who understood energy issues and the need to move toward a renewable energy future. In my opinion they should have taken more steps to put us on that path, and they didn’t. I’m still angry.

The Clinton/Gore years were followed by the Bush/Cheney years where the energy focus was on fossil fuels and nuclear power. It was a discouraging period for renewables and we lost valuable time while the rest of the world began to make significant progress in their development and deployment of renewables. We clearly lost out on the economic activity and jobs that were going to other countries as the new, clean energy industries were being developed. It was only with the coming of the Obama administration that this situation began to change, but our progress has been seriously slowed down by a dysfunctional Congress these past few years, the worst I have seen in all my years in Washington, DC.

Let me also say a word about the role of traditional energy companies in the oil, natural gas, and coal industries. Clearly their role in supplying energy would be affected by the penetration of renewable technologies, and they have reacted as one might expect. In the mid 1990s, as renewables began to emerge, the coal industry sponsored several studies that attacked the ability of renewables to provide a significant fraction of national energy needs. These studies were not accurate, even misleading, and required a great deal of effort to refute. I’ve always thought of them as similar in intent to the studies sponsored by the tobacco companies to raise doubts about the health effects of smoking and slow down regulatory activities. Modern analogs are the studies sponsored by fossil fuel companies to disprove global warming and climate change and slow down efforts to reduce dependence on carbon-based fuels.

A plague
This is not to say that fossil fuels don’t have an important role to play in our future energy supply. Renewable technologies are not ready yet to provide the large amounts of energy required to power our economy and fulfil our international responsibilities, and probably won’t be for several more decades. Nevertheless, recent studies document that renewables can provide the major share of our electrical energy requirements in 2050 if we have the will to do so and make the necessary investments (see ‘Renewable Electricity Futures Study’, NREL, June 2012). It is also true that our transportation fleets are highly dependent on petroleum-based fuels, and will be for many years until they are electrified and alternate liquid fuels are developed. Also, natural gas has always been recognized as a needed transition fuel to a renewable future. With the U.S. and other countries entering a new natural gas era with the emergence of large amounts of shale gas via fracking , and the ability of natural gas to substitute for coal in power generation and thus reduce carbon emissions, it will be an important part of our energy supply for decades to come. Unfortunately, this glut of shale gas may lead to reduced investments in renewables if national energy policies don’t take this into account.

To sum up my views on why more hasn’t happened in the U.S. since February 1979 when the DPR was released to the public and provided an excellent framework for moving toward a renewable energy future: a plague on all houses. Too many Republicans and some Democrats have been too protective of traditional energy companies, Democrats have often failed to provide needed leadership when opportunities presented themselves, and fossil fuel companies, particularly coal companies, are generally doing what they can to protect their vested interests. However, it is also fair to recognize that several oil companies did invest resources in the early days of photovoltaics to help get things started, as Peter Varadi well documents in his newly published book about the history of PV ‘Sun Above the Horizon’ (Pan Stanford Publishers). Nevertheless, they mostly retreated from these investments when they realized that short term profits were not available, and that a long term perspective would be required.

Today, in my opinion President Obama ‘gets it’ about the promise and importance of a renewable energy future.

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I believe he is doing what he can to put the U.S. on that path but is facing serious opposition from a too often recalcitrant U.S. Congress. In my view Congress has an obligation to look down the road, anticipate national needs, and take positive steps to address those needs before they become crises. This is an obligation I believe recent Congresses have often not met. We can do a lot better and must if the U.S. is to derive its fair share of benefits from an emerging and inevitable clean energy industry that other countries are working hard to develop and know is the future.

Energy Storage: A Critical Link In the Renewable Energy Chain

An issue that has always grabbed my attention is the critical role I and others foresee for energy storage in the eventual widespread use of variable (intermittent) renewable energy sources such as wind and solar. In fact it was the focus of my first decision when I assumed responsibility for DOE’s renewable electricity programs in 1994. That decision was to establish a comprehensive storage program to complement the established generation programs – up until that point the only storage program was a small effort on underground hot water storage at a university in South Carolina (no doubt related to the fact that the Chairman of the relevant budget authorization subcommittee was from South Carolina). The new program, in addition to thermal storage, added battery storage and superconducting magnetic energy storage (SMES) – superconductivity was another of the programs I managed.

Energy storage is one of two critical renewable energy issues that I have always said I would ‘fall on my sword for’. The second is the need for a national smart grid that will allow renewable electricity generated in one part of the country to be shared with other parts. I have touched briefly on the energy storage topic in earlier blog posts; this post takes a much more detailed look at various storage options.

The need for storage to steady the output from a variable energy source is not new. In fact, in December 1861 the following words and illustration appeared in an agrarian newsletter:
“A Mighty Wind One of the great forces nature furnished to man without any expense, and in limitless abundance, is the power of the wind. Many efforts have been made to obtain a steady power from the wind by storing the surplus from when the wind is strong. One of the latest and simplest of these is illustrated in the accompanying engraving. A windwheel is employed to raise a quantity of iron balls, and then these balls are allowed to fall one by one into buckets upon one side of a wheel, causing the wheel to rotate, and thus to drive the machine.”

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If one substitutes water for the iron balls and attaches a generator to the rotating machine you have today’s system of pumped water storage and generation. A modern version of the 1861 system, using gravel instead of iron balls, is shown in the following sketch:

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Since the discovery of electricity generation using rotating coils of wire in magnetic fields by the British scientist Michael Faraday in 1820, people have sought ways to store that energy for use on demand. Without such storage, or use in some other way (e.g., to electrolyze water to create and store hydrogen, heat water, bricks or phase change materials that store heat , or refrigerate water to create ice) surplus electricity generation is lost. With modern societies increasingly dependent on energy services provided via use of electricity, the need for electricity storage technologies has become critical. This is especially true as more and more variable renewable energy enters the grid, to avoid grid destabilization. This can occur because electric power supply systems must balance supply and demand, and because demand is highly variable and hard to control the balancing is routinely achieved by controlling the output of power plant generators. If these generators are variable solar and wind, and their grid contribution becomes significant, achieving the balance is that much more difficult, and a means of stabilizing these variable outputs is needed.

There is also strong economic and social incentive for storing electricity in a localized, distributed manner. Today’s 100-year-old centralized utility business model, in which large central power plants deliver electricity to customers via transmission and distribution lines, includes the imposition of peak demand charges that can account for a significant fraction of a business’ or an individuals’ electricity bill. With the use of localized generation (e.g., PV panels on your roof), combined with storage at your site, these demand and peak charges can be reduced if not eliminated, and independence from the utility, to some degree, can be achieved. This reality is taking place in Germany (and coming to the U.S.) and threatening the utility business model in Germany to the extent that German utilities have gone into the solar-energy storage business. They now sell or lease or maintain roof-mounted PV and battery storage systems.

Today’s menu of devices that allow storage of surplus electricity for use at other times includes: solid state batteries and supercapacitors, flow batteries, flywheels, compressed air energy storage (CAES), and pumped hydropower. Hydrogen generated from any electricity source via electrolysis of water, and combusted or used in fuel cells, is, in many ways, the ultimate storage technology for surplus electricity. Flywheels, pumped storage, and fuel cells are discussed in earlier blog posts ; other storage technologies are discussed below.

Historically, electricity has been stored in lead-acid batteries, and this is still the dominant battery storage technology today in cars and elsewhere because of low cost, high power density, and high reliability. Disadvantages are low specific energy storage capacity, large size, high weight, and the need for an acid electrolyte. Lead is also a toxic material. Research to improve batteries has been underway for more than a century, and considerable progress has been made (e.g., improved lead-acid batteries that require no maintenance and recycling of used batteries to recover the lead), with considerable promise for further developments in the future.

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Most battery attention today is focused on lithium-ion batteries where cost and safety are prime concerns. Research into post lithium-ion batteries is also being actively pursued.
Lithium-ion batteries are widely used today because! “pound for pound they’re some of the most energetic rechargeable batteries available.” For example, it takes six kilograms of a lead-acid battery to store the same energy as one kilogram of a lithium-ion battery. Lithium-ion batteries (there is a variety of battery chemistries) also hold their charge well (losing about 5% per month), have no memory effect (therefore no need to fully discharge before recharging), can handle many hundreds of charge/discharge cycles, and have good ’round trip efficiency’. The story does have a negative side – lithium-ion batteries are sensitive to heat, can’t be fully discharged (thus requiring a computerized battery management system), are still costly (although costs are coming down), and certain chemical formulations can occasionally burst into flame if damaged or otherwise overstressed. One person making a big bet on lithium-ion batteries is Elon Musk, who has announced plans for a $5 billion battery factory, to provide lithium-ion batteries for his Tesla electric vehicles and other applications. Through such large scale production Musk hopes to reduce the cost of the batteries by 30 percent (to about $10,000 for a 60 kWh battery pack).

Supercapacitors store energy in electric fields and fill a gap between ordinary capacitors and rechargeable batteries. Their claim to fame is that they can be charged/discharged much more rapidly than batteries and can tolerate many more charge/discharge cycles. They are widely used as low current power sources for computer memories and in cars, buses, trains, cranes and elevators, including energy recovery from braking.

Redox (reduction/oxidation) flow batteries are large scale rechargeable energy storage systems that are on the verge of wide application in the electric utility sector. They are particularly well suited to storing large amounts of energy, e.g., the surplus energy created by hours of solar or wind power generation. The energy storage materials are liquids that are stored in separate tanks, and when energy is needed the liquids are pumped through a ‘stack’ where they interact to generate electricity. Many different chemical liquids have been tested for flow battery operation, with most current attention being focused on vanadium compounds which are expensive. Flow batteries also have relatively low round-trip efficiencies and response times. Because of the vanadium cost concern many other chemical possibilities are being evaluated.

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CAES (compressed air energy storage) utilizes surplus electricity to compress air to high pressures in large caverns, which can then be heated and released as needed to power expansion turbines that generate electricity. Such a CAES system has been operating successfully in Alabama since 1991, and gases other than air (e.g., carbon dioxide) can be used as well.

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SMES stores energy in the magnetic field of a circulating dc electrical current in a superconducting coil. The superconductor has no electrical resistance and the current continues indefinitely unless its energy is tapped by discharging the coil. A typical SMES device has two parts, a cryogenic cooler that cools the superconducting wire below its transition temperature at which it loses its electrical resistance, and power conditioning circuitry that allows for charging and discharging of the coil. Its advantages are ultra fast charge and discharge times, no moving parts, nearly unlimited cycling capability, and an energy recovery rate close to 100 percent. Disadvantages are cost of the wire, the need for continuous cooling, large area coils needed for appreciable energy storage, and the possibility of a sudden, large energy release if the wire’s superconducting state is lost. SMES devices are often used to provide grid stability in distribution systems and for power quality at manufacturing plants requiring ultra-clean power (e.g., microchip production lines). One MWh SMES units are now common and a twenty MWh engineering test model is being evaluated.

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To summarize, there are many energy storage options that work and tradeoffs are often required – e.g., among storage capacity, power capacity, round-trip efficiency, and most importantly cost. Lots of research is underway to reduce costs, given the large potential markets and the need to safely integrate variable renewable energy generation from solar and wind into the utility grid system. I have no doubt that cost-effective storage systems will soon be available, facilitating the needed rapid transition to a renewable electricity future.

Peter Varadi’s New Book: ‘Sun Above the Horizon’

I have had the privilege of being Peter Varadi’s friend for the past several years, and am pleased to bring this important book to your attention. It is a unique and valuable contribution to the history of solar photovoltaics (PV) authored by a true solar energy pioneer.

I will let his brief bio speak for itself: “Peter F. Varadi escaped from Hungary in 1956 and after a distinguished scientific career was appointed head of the Communication Satellite Corporation’s (COMSAT) chemistry laboratory in the U.S. in 1968. In this function he also participated in research on photovoltaic (PV) solar cells, which were used to power the satellites.
In 1973 he co-founded SOLAREX Corporation, Rockville, MD (USA) to develop the utilization of solar cells (PV) for terrestrial applications. SOLAREX was one of the two companies which pioneered this field. By 1983 it had become the largest PV company in the world when it was sold to AMOCO. Following that he continued consulting for Solarex for 10 years and after that for the European Commission, The World Bank, the National Renewable Energy Laboratory, and other solar energy organizations.
In 2004, in recognition of his lifelong service to the global PV sector and his continuing commitment striving for excellence in the PV industry, Dr. Varadi received the European Photovoltaic Industry Association’s (EPIA) John Bonda prize. He is a Fellow of the Washington Academy of Sciences.”

I have also had the opportunity to review Peter’s new, 548 page, book prior to its publication by Pan Stanford Publishing in paperback on May 23d ($24.95) and in hard cover ($69.95) on June 10th. At Peter’s request the book is being offered at a 20% discount ($19.96 and $55.96) and free shipping until August 31st. To obtain this discount please go to:
http://www.crcpress.com/product/isbn/9789814613293 (paperback)
http://www.crcpress.com/product/isbn/9789814463805 (hard cover)
In both cases use the special saving code PAN01 (numeric zero).

I believe the best way to express my enthusiasm for this book is to reproduce some of my review comments submitted to the publisher:

“The book is a unique contribution to the history of solar PV electricity, an energy technology that is transforming the way we generate and use electricity. No other book that I know of puts this history together.

As someone who is intimately familiar with the development and deployment of renewable energy technologies, which I have been studying and working on since 1969, I can nevertheless truthfully say I learned a great deal I did not know about the PV industry’s early years and its subsequent expansion into a critical part of the world’s current and future energy system. The audience for this book will include lots of people like me who have lived through these early days and can relate to much of the history, but also the rapidly increasing number of people in the PV industry around the globe, and the growing number of young people, all over, who are committed to cleaner energy systems and will enter the field. This includes technically-oriented as well as business-oriented people who will benefit greatly from Peter’s wise business insights. In my opinion, as a former academic, it is also textbook material at several academic levels.

I might add that the environmental, development, and public health communities will find the book useful as well as they apply photovoltaics to providing basic human energy needs, reducing carbon emissions from power generation, and helping provide potable water for drinking, sanitation, and food production.”

“”Based on some personal experience teaching at various levels, I could see this book being used as supplementary, and even primary, reading in high school, undergraduate and graduate courses. This would include a broad range of students, both technical and non-technical, and I could easily see myself using this book in an energy course I would teach. It would also have a history and government audience.”

“PV is a powerful transforming technology that is being increasingly applied in both developed and developing countries. The audience for this book will be global.”

“I am unaware of any other book that addresses this history as comprehensively as this book does. It also benefits greatly from being written by a true pioneer who helped create a new and critically important industry. It is a history that needed to be told and I can think of no one better than Peter Varadi to tell it.”

You can tell that I am enthusiastic about this book. It has a structure that carefully lays out the history and anticipates the future.

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Human Wastes: Another Energy Resource Waiting to Be Tapped

Recently I posted a blog entitled ‘Animal Wastes: An Energy Resource That Is Win-Win’. The Washington Post article reproduced below may be considered a follow-up to that blog but focused on using human wastes to generate energy. It usefully points out the several beneficial uses to which human wastes can be put and the economic benefits of doing so. It is worth reading!

…………………………………

WASTE, NOT WASTED
By Ashley Halsey III
Washington Post (April 6, 2014)

This is a topic that one must approach delicately so as not to offend the reader’s sensibilities, but since it is a matter of importance for which you may receive a bill for some portion of $470 million, we start out with an analogy.

You need energy, so you eat. Through the miracle of digestion, your body sorts what you have eaten, say, a pastrami on rye with a glob of coleslaw and a dill pickle, and plucks out the nutrients — proteins, carbohydrates and sugars it needs to generate power. Then it jettisons the rest.

What your body jettisons disappears forever, carried along in a huge network of sewers to a plant in the southeastern corner of Washington.

Just like you, that plant needs energy. Through a miracle called thermal hydrolysis, it soon will be able to sort through what you have jettisoned and use it to generate electricity.

Yes, from poop will come power — 13 megawatts of it. Enough electricity to light about 10,500 homes.

Ben Franklin never dreamed of this one.

While Ben may have denounced the scheme as impossible sorcery, he also noted that a penny saved is a penny earned, so he might have been at least intrigued by this notion.

More than a few pennies may be saved for the citizens of the District and for some Virginians and Marylanders. Those people — 2.2 million of them — get a monthly bill for the privilege of sending their thoroughly digested nutritional intake to the plant in Southeast Washington operated by D.C. Water.

A chunk of that monthly bill is passed on to another local utility — Pepco. D.C. Water is the electricity company’s No. 1 customer. By converting poop to power, the water company will cut its Pepco bill by about one third and reduce by half the cost of trucking treated waste elsewhere.

But enough about poop, a subject that makes many a reader a bit squeamish. Because we’d rather not drive you away from the description of a wholly remarkable plan that is very likely to affect your pocketbook, henceforth we will refer to the matter that flows through the sewage plant as “the product.”

In fact, you soon will learn, it is going to be turned into a genuine product. One with a price tag. One that you may buy back.

Think about it.

The product has shed the label “wastewater” to morph into something called “enriched water,” a term laden with many more intriguing possibilities.

“It could be a game changer for energy,” said George Hawkins, an environmentalist who became general manager of D.C. Water. “If we could turn every enriched-water facility in the United States into a power plant, it would become one of the largest sectors of clean energy that, at the moment, is relatively untapped.”

What’s nearing completion outside Hawkins’s office window, however, is something never built on this scale anywhere in the world. A decade of study came first, and to see whether the system would work here, D.C. Water paid smaller European utilities that use the same process to modify their product so it more closely matched that which Washington produces.

“We’re confident that this model will work,” Hawkins said.

Something called the Cambi, for the Norwegian company that builds it, sits at the heart of it.

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When the product flows into the more than 150-acre plant known as Blue Plains, it goes through a couple of mesh filters to shed the debris swept up in the sewer system. Then it goes through a treatment process that turns it into what the Environmental Protection Agency categorizes as class B waste, enough to fill 60 big dump trucks with 1,600 tons of product every day.

And out the gate it goes, at a cost of $16 million a year.

That will change in May and June, as D.C. Water begins a phase-in intended to get the new system into full service by January.

Here’s how it works:

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A centrifuge drains off the liquid, and then the screened product will flow into four pulpers, tall stainless steel vats that look like Gulliver’s soda cans. Steam recycled from farther down the process is used to preheat it, and then it flows into one of the two dozen Cambis. They sit like a row of gleaming, blunt-nosed rockets, but they serve as pressure cookers.

The product is heated to more than 320 degrees under as much as 138 pounds of pressure for 22 minutes. Then it moves to a flash tank, where the temperature and pressure drop dramatically and a critical change takes place.

“Because of that pressure difference, the cells burst,” said Chris Peot, director of resource recovery at D.C. Water.

When the cells burst, the methanogens can have their way with them.

That happens in the digesters. They are four huge concrete vats, 80 feet tall and 100 feet in diameter. Right now, their interiors are like vast cathedrals, with domed ceilings and a shaft of light glancing through a hole in the top.

When the whole operation gets rolling, inside them is not a place you would want to be. The product will flow in from the four flash tanks, mixing with the methanogen microorganisms. Methanogens create marsh gases. In the digestive tracts of animals and humans, they also create gas, to the particular delight and fascination of middle-school boys.

That’s what this is all about — creating methane to generate electric power.

The temperature inside the digesters is kept at about that of the human body: 98.6 degrees Fahrenheit. Each digester chamber has five vertical blue tubes, as big around as manhole covers, that suck the product from the bottom and recycle it to near the top. After the product stews there for about two weeks, the methane produced by the process will vent out a 12-inch diameter pipe in the crown.

After a bit more purification, the methane will be used to fire three jet turbine engines that create electricity. A byproduct of that process: steam, which is funneled back to the pulper.

The power portion of the plant will be operated under contract by Pepco. The deal doesn’t allow D.C. Water to sell the power it generates, a moot point since the process of creating it eats up 3 megawatts and the remaining 10 megawatts will be sucked up by operations at Blue Plains.

Once the digester’s work is done, the remaining product will be drained out into dump trucks, but their total load will be cut in half to about 600 tons a day.

Remember that we told you earlier that what you jettison disappears forever? Let’s reconsider that, because there’s actually a chance you’ll see it again. In a strikingly different form. Right back where you saw it first: on your dinner table.

The product that has been trucked from Blue Plains is rated class B. But the product that comes out of the digester will be rated class A.

The difference?

Class B still has some bad stuff in it. Most of it is shipped to farmers, some in Maryland but most of them in Virginia. They get it free, but unless they let it sit for at least a month, and sometimes up to 18 months, the only things they can use it to fertilize are trees and sod used by landscapers.

Class A product can be used right away on anything, including fields that grow the fruits and vegetables you buy at the grocery store and serve for dinner.

That’s because, Peot says, in the Cambi, “All the pathogens are completely obliterated.”

“Our product has these super-elevated levels of these naturally occurring, extremely important plant hormones,” Peot said.

It is a more environmentally sound choice than the chemical fertilizer alternatives. In the raw, the class A product is so potent it needs to be cut with other materials before it is used to fertilize crops.

“We can blend this with sawdust and sand and make a topsoil substitute for use in green infrastructure projects,” Peot said. “We’re still going to go to farms while we try to build the market for this product.”

Hawkins, D.C. Water’s general manager, chimed in: “It’s clean, organic fertilizer. Conceivably, we could sell this product at Home Depot. ”

Unlike most innovations in waste treatment locally and nationwide, this project was not mandated by a federal court order. D.C. Water’s board decided it was a worthwhile investment of ratepayers’ money.

“This was one of the easier $500 million decisions that we’ll ever ask the board to make,” Hawkins said, ticking off the value: a savings in electrical costs of about $10 million a year; lowering the cost of hauling away treated waste; the potential to generate a profit by selling the product; a reduction by one third in the plant’s carbon footprint; and one more critical virtue.

For about three days a month ago, residents of part of Northwest Washington were told to boil their drinking water for fear it might be contaminated. That scare was caused by a power problem that shut down a pumping station.

“It wasn’t Pepco’s problem. It was internal to us,” Hawkins said. “We have great fears here about what would happen if there was a catastrophic power failure and Blue Plains stopped.”

Generating power internally will provide enough juice to keep the basics running, were that to happen, he said.

“This is the rare combination of both environmentally and economically positive,” Peot said.

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A Cambi installation in the UK