70% Renewable Energy By 2035? Physics Vs. Politics

Japan and Climate Change: Not As Bad As It Seems, Part III

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How much of Japan’s electricity can be generated by renewable energy (RE)? America’s Berkeley National Laboratory and Japan’s Ministry of Economy, Trade, and Industry (METI) have very different assessments. I think Berkley’s is more realistic.

            According to Berkeley Lab, by 2035, it is both technologically and economically feasible for Japan to get 70% of its electricity to come from RE, mostly solar and wind. Moreover, doing so would lower wholesale electricity costs by 6% from the 2020 level.

            Berkeley’s vision is a mirage, contends the Ministry of Economy, Trade, and Industry (METI ), which contends that geography and the laws of physics create insurmountable barriers. Solar and wind need an enormous amount of suitable land, but Japan lacks enough of such land. 66% of the country is covered by forests. Moreover, due to the earth’s tilt and Japan’s mountainous topography, a square meter of land in Japan gets less energy from sunlight than in many other countries. Wind power needs certain wind conditions and Japan has only a few suitable areas for onshore wind or near-offshore wind, while far-offshore wind will not be economically practical on a mass scale for many years to come. Then, of course, the sun does not always shine, nor the wind always blow. So excessive reliance on RE, METI officials argue, makes brownouts and blackouts more likely. Consequently, METI concludes, Japan is forced to adopt more modest goals for RE, while greatly expanding nuclear power and maintaining its reliance on fossil fuels for decades to come.

            It is telling, then, that Berkeley Lab excluded any unsuitable land and still found enough sites to support its RE goals. Moreover, while the World Bank includes Japan in a list of countries with less solar potential, it noted that, even in such countries, “the potential is not dramatically lower compared to the top-performing group.”

            Before going into the details of why I believe METI is unduly pessimistic, it’s worth recalling that, despite the Ministry’s role in pioneering the commercial use of solar power decades ago, METI has repeatedly underestimated RE’s potential.  For example, in 2018, METI said it would take until 2030 for RE to reach 22-24% of electricity generation. In reality, Japan already reached 22% last year. By contrast, in a 2015 report commissioned by the Ministry of Environment, the Mitsubishi Research Institute projected that renewables could comprise 33-35% by 2030, close to the goal pushed through by former Primer Minister Yoshihide Suga in 2021.

Berkeley’s Vision Versus...

In the Berkeley Lab scenario, by 2035, 90% of Japan’s electricity could come from emissions-free sources, of which 70% would be generated by RE and 20% by nuclear power. The remaining 10% would come from natural gas, down from 37% in 2019. Coal would be completely phased out. Attaining these goals would reduce Japan’s carbon emissions from the power sector by 94% from 2019 levels, an amount equal to 30% of Japan’s total emissions.

            The RE portion would require an investment of ¥38 trillion ($283 billion) over 15 years, amounting to 0.5% of 2022 GDP per year. This investment would cover not only RE generation but also upgrading the electrical grid. The latter includes smart technology and storage capacity to handle the peaks and valleys of RE as well as interconnections among Japan’s nine regions, which are now mostly isolated from each other. With nuclear and gas acting as baseload power, and batteries and grid upgrades outflanking the problems of solar and wind intermittency, Berkeley says Japan need not fear blackouts or brownouts. Yes. ¥38 trillion is a lot of money, but METI has proposed spending ¥150 trillion ($1.1 trillion) of public and private money over the next decade or so on a GX (Green Transformation) program, including ¥60 trillion ($430 billion) on power from sources like RE, nuclear energy, hydrogen, and ammonia.

            To reach the Berkley target, solar power would have to resume rising at the record pace reached in 2015 and wind at twice its record. The scenario assumes that Japan does not raise its minuscule carbon tax (¥289 per ton); if it did, progress would be even faster. So, this is not a forecast of what will happen—since growth in RE has slowed down—but an assessment of what would be attainable if the political will were there.

            If public fear of another accident prevents nuclear energy from getting back to 20% of electricity, then more natural gas would be needed, reducing the decarbonization benefit.

... METI ’s Vision

METI touts a very different vision, one where co-firing coal and gas plants with ammonia and hydrogen, the use of Carbon Capture and Storage (CCS), and exports of natural gas power plants to developing countries, can all combine to preserve coal and LNG electricity, and not only within Japan. Rather than help developing countries with a coal-to-RE transition, Tokyo is pushing a coal-to-gas transition.

            METI’s 2021 Strategic Energy Plan projects that in 2050, when Japan has pledged to reach net zero emissions, renewables will generate just 50-60% of electricity, 30-40% will come from some mix of nuclear and “decarbonized” fossil fuels, and 10% from hydrogen/ammonia. In private, METI officials insist that Suga’s 2030s goals for 2030 and 2050 are “ambitious,” their polite word for unrealistic. It is telling that the 2023 report of the METI-affiliated Institute for Energy Economics Japan (IEEJ) predicted in its base case for 2050—i.e., no heroic assumptions about technological progress in green hydrogen or CCS—that coal would still generate 18% of electricity and natural gas another 36%, while solar, wind, geothermal, and hydro combined would provide just 26%. Even in the Advanced Technologies scenario, fossil fuels would supply 18%, while solar, wind, geothermal, and hydro combined supply just 45% (see table below).

What Is “Land”?

In 1858, petroleum oozing from the ground was a nuisance. That all changed a year later with the advent of drilling for oil in Pennsylvania. First, it replaced whale oil in lanterns and then went on to increasingly displace coal. Today, it’s metamorphosing from a resource into a threat.

            Whether something is a resource or a threat is not a fixed matter, but one determined by technology and economics. And this is what METI’s calculations miss. Solar power does not need land per se. What it needs is a surface where sunlight can hit the panels at the proper angle and with sufficient intensity. Technology is increasing the kind of surfaces that are suitable and cost-efficient. Yes, larger surfaces yield more energy per square meter than small ones, and flat surfaces are better than curved. But solar panels on rooftops and mountainsides and even lakes are already being used. There are even solar film panels that can be put on windows. So, while using inferior sources does make solar more expensive and less efficient, it can overcome the obstacles METI cites.

            These technological innovations are gradually being recognized. The Tokyo Metropolitan Government has mandated that, beginning in 2025, big contractors of detached homes less than 2,000 square meters (21,500 square feet) must install rooftop solar. Residences emit almost a third of all carbon in Tokyo prefecture, home to 10% of Japan’s population. Business and apartment buildings with floor space of more than 2,000 square meters were already required to have rooftop solar.

            Moreover, even while talking of the limits to RE, METI is introducing an incentive scheme—called the Feed-in-Tariff—for rooftop solar on industrial and commercial buildings across Japan. When combined with other plans for rooftop solar for government buildings and public lands, the Ministry of Environment projects that, over the coming years, this could add 20 GW of electricity. That compares to the 90 GW of cumulative solar that will be in place by the end of this year. This does not even count rooftop solar for homes. So, METI certainly supports RE. However, it doesn’t want its share to be “too large.”

Solar Farmland: From Agrivoltaics to Abandoned Farmland

One innovation particularly important in Japan is the spread of agrivoltaics: putting solar panels a few meters above crops as in the diagram at the top. Agrivoltaics not only adds to available siting opportunities, but adds some other benefits. Being above the ground keeps the panels a bit cooler, which improves electrical output. Meanwhile, partial shade means that plants lose less moisture through evaporation, and that improves crop yields for some plants and creates small reductions for others. Due to high incentives, which have now been reduced, one farmer in Chiba prefecture was able to earn ¥24 million ($174,000) by having solar panels covering one hectare (2.5 acres) of his farm and selling the excess to the grid. That’s more than he earns from farming itself.

            Unfortunately, only 742 hectares were approved for agrivoltaic use between fiscal 2013 and 2019, just 0.017% of Japan’s total farmland of 4.4 million hectares (17,000 square miles). By contrast, South Korea has targeted 10 gigawatts (GW) of agrivoltaics capacity by 2030. The biggest player is China, which, as of 2020, generated two-thirds of the current global total of 2.8 GW. The technology is just getting off the ground, so to speak. 

            Then there is all the abandoned farmland that could be used for solar farms, except that current regulations prevent it. As of 2015, about 5,400 sq. kilometers of Japanese farmland had been abandoned as farmers died without successors, an amount adding up to about 12% of all farmland. Given a conservative estimate of around 37 gigawatt-hours (GWh) of solar electricity per square kilometer in 2010, this abandoned land alone could produce more than 200 terawatt-hours (TWh) of electricity if used for solar over the coming decade, more than twice as much as Japan’s current solar output. That means solar power could supply 30% of Japan’s 2022 level of electricity consumption, up from the 10% it actually supplied. When Taro Kono was Administration Reform Minister, he tried, and failed, to end these restrictions on using abandoned farmland.

As time passes, even more farmland will be abandoned as elderly farmers pass on At the same time, solar’s potential will increase even more as improving technology is estimated to enable solar to provide at least 63 GWh/sq. km by 2050.

How Much Is Possible?

A group of scholars compared land use for solar in Europe, India, and Japan/Korea (taking the latter two countries as one unit due to their land use similarities). What they found was that, by 2050, solar could supply 46% of Japan/Korea’s needed electricity using just 3% of the total land in the two countries, together with rooftop solar that would supply 14% of solar energy in 2050.

            Here’s the bottom line: the main obstacles to faster adoption of RE in Japan are not geographical/physical limits or cost. It’s primarily regulations, business practices, and government policy. Abandoned farmland is just one example. During times of peak usage, utilities are still able to curtail renewable access to the grid in favor of fossil fuels and nuclear. And lengthy approval processes and other obstacles make building efficient megasolar projects harder and more expensive than they need be.