Some experts on acquiring energy from new resources have declared that in 2018 there was an “Energy Storage Revolution”.
What does it mean? That energy storage was invented? No, definitely not, large scale energy storage devices – such as pumped storage hydropower plants (see Chapter 5, Section 5.4) – have been built since the late 1800s. Perhaps there was a sudden extraordinary increase in the construction of new energy storage facilities? No, more were indeed built than a year before, but it can hardly be viewed as a “revolutionary increase”. So what?
In the opinion of this Author, there has been a revolutionary increase in awareness that a full “decarboniation” of energy production may never be achieved without the development of a grand-scale storage technology.
Why may it never be achieved? Well, let’s take a look at the zero-emission methods of generating electric power. According to the Energy Information Agency, their current (2018) contribution to the overall power generation in the US is 36%; the numbers in parentheses show the contribution of each of the listed sources:
- Wind turbines (6.5%);
- Solar PV panels and CSP plants (1.5%);
- Hydropower plants (7.0%);
- Nuclear power plants (19.4%);
- Methods utilizing biomass (1.4%);
- Methods using geothermal sources (0.4%).
- Methods utilizing ocean waves, tides and tidal currents (< 0.1%);
A number of USA States (e.g., California, Oregon and Washington, Massachusetts, and many others) have already made commitments to attain a 100% or 80% economy-wide greenhouse gases emission reduction by 2050. European Union has just (December 13, 2019) announced an ambitious goal to “make Europe the very first climate neutral continent by 2050”.
So, if all fossil-fuel burning power plants are to be eliminated, they must be replaced by zero-emission power generation methods listed above. Con- sider the scale of the problem. There will not only be need to create new zero-emission with total power of 64% of the current US generation. Much more will be needed, because gasoline and diesel cars and trucks have to be replaced by electric ones. So, even more generation will be needed for charg- ing all those vehicles. How much? There are only some estimates, e.g., in in a CITYLAB Web page. It seems that not only 64% of the current generation will be needed, it may be 100% or even more.
Which of the seven methods listed above offers the greatest chance that it will be able to satisfy these enormous new requirements? Let’s evaluate it for each of them, from the bottom up.
Ocean waves and tides, as presented in Chapter 7, may provide huge amounts of energy. However, the methods of harnessing them are not yet sufficiently developed. They may play a meaningful role in global economy in a more distant future than the 30 or 50 years from now, which is a widely accepted necessary “target date” for attaining global decarbonization.
Geothermal energy, as discussed in Chapter 8, has the potential of satisfying all the needs of humanity – yet, reaching these resources would require drilling a huge number of very deep wells. Again, heat and electricity generated from geothermal resources may become major contributors in the future global “energy budget”, but a realistic time period needed to develop this sector is definitely much longer than the 30 or 50 years in question.
Biofuels are a great sources of “carbon neutral” energy. They will play an important role in the 30-year plans of decarbonization: most likely, there will be no other way to make air transportation fully eco-friendly than to replace current jet fuel derived from petroleum by fuel of nearly identical properties, but derived from biological products. It can be expected that the production of biofuels will increase several times over the next 30 years – but to replace all energy based on fossil fuels it would have to increase several dozen times.
Hydropower is patently zero-emission. Currently, the electric energy it provides is more than one tenth of that obtained from fossil fuel burning. It produces about 16% of the electricity generated globally (about a quarter of electric energy obtained from fossil fuels). But existing resources with easy access have already been used to a large extent. Also, there are other concerns – even though hydropower does not emit any CO2, it’s not com- pletely “benign” for the environment. Currently, some hydropower facilities in Oregon are being destroyed because of their negative impact on biosphere. As far as new hydropower ventures are concerned, the attention is focused primarily on pumped-storage plants (see Chapter 5) which do not generate new power, but only store surplus power for later usage.
Nuclear power. It’s zero-emission and generates more than 10% of electric energy globally. In principle, it’s capable of generating much more – it could even replace all fossil-fuel generation if enough new reactors were built. The only limitations here are the high up-front costs – which is probably not an insurmountable obstacle – and the negative public perception of nuclear energy. The latter seems to be an obstacle much harder to overcome than the financial barrier. Some nations, e.g. China, or , Russia, have far-reaching plans to develop nuclear power. So, nuclear energy will certainly play a role in global decarbonization, but most likely it won’t be the principal player in this process.
Wind and solar power. By eliminating all other candidates, we come to the conclusion that the main burden of global decarbonization must rest on these two technologies. Possible? Yes, definitely, the existing resources have only been used to a minimal extent. There are huge “resources” of off-shore wind power. There are large areas of lands (e.g., deserts) where stationary PV panels may be deployed and many bodies of water available for “floating” PV panels mounted on big “rafts” – without any depletion of areas that can be used for agriculture, for recreation, or for new human settlements.
But there is one major problem: namely, generation by means fossil fuel burning can deliver power in a stable manner, according to consumer require- ments. In the case of generating electricity by geothermal, hydropower and nuclear methods the situation is very similar. But not with wind and solar power. And this is the heart of the problem!
Why? In contrast to other methods of harnessing renewable energy, wind power and solar power are intermittent. In the case of solar power, there is regular intermittency (it’s on at daytime, and off at night) and random intermittency, due to cloudy skies. The latter is troublesome especially in medium latitudes (e.g., in most European countries). The intermittency of wind power may be even more chaotic. There are regions on the globe where the wind is highly regular and predictable – namely, in areas where tradewinds blow (see Chapter 6). Unfortunately, they blow mainly over open oceans – which is good perhaps for sailing ships, but definitely not good for wind turbines.