In Canada we are already producing enough hydro power to meet 100% of our needs for electricity if we did not waste so much of it on thermal applications that can be more cheaply met by using thermal storage. Moreover thermal storage would make it possible to increase our hydro capacity in the future by utilizing the hydro capacity that is currently being lost during periods of high water flow. See the journal Sustainability for details.
As Tracy Dahl and others have pointed out it is not necessary for renewables to provide 100.00% of the energy we need. For buildings we use energy in two forms: thermal and electrical. While both forms of energy can be stored that is easy and economical to achieve for thermal energy but is currently expensive for electricity, but considering the brief duration and power consumption needed from a generator backup that does not represent a real problem.
If you use the exergy storage solution described in my previous comment (detailed in
http://www.mdpi.com/2071-1050/6/11/8297 ) then essentially all of the energy that is needed in Canada in both forms (thermal and electrical) can be drawn from energy sources that are presently just going to waste. The extra electricity comes from the capacity of such stores to store the exergy from the existing hydro dams, especially for run-of-the-river stations that lack the water storage capability of high dams. The extra thermal energy comes quite literally out of thin air!
The US has comparatively less hydro generation but the exergy stores can boost the capacity factor from any renewable energy source, such as wind, solar, etc., so exergy storage still provides an economical solution. As you travel south the annual need changes from the net need for heating to a net need for cooling. Exergy stores can store cold as well as heat (and do so even in the north) so the design may be somewhat different but the capability is still available except in places that have small temperature swings like Hawaii. Seasonal storage of cold is currently employed on a large scale in Toronto.
Solar thermal collectors feeding ground exergy stores are about six times more efficient than solar PV panels, and they make a much bigger contribution to the power grid as well. Instead of feeding power into the grid they reduce the building's demand for electricity for applications like space heating and cooling and for hot water. In the process they can also store electricity, absorbing it at night when there is ample supply instead of drawing electricity during the day. See the November/14 issue of http://sustainability-journal.ca to see how this concept could eliminate the need for fossil fuels for both thermal and power generation applications in Ontario.
If you could store wind power, and solar power, and hydro power, and thermal power, and nuclear power in storage facilities akin to batteries then you could match the energy supply and demand using whatever mix of those energy sources is available in any country or district. If you grasp the concept of exergy storage then you will realize that exergy storage provides an affordable, high capacity means of matching all of those energy supplies with both our thermal and our electrical needs. A single component - the exergy store - concurrently handles the need to store both heat and electricity, with the caveat that the electricity is returned in the form of electricity demand reduction.
The FERC update completely ignores the largest and most readily available sources of renewable energy and it incorrectly assumes that the peak demand for energy must be met by generation, neglecting the potential to meet a large part of that peak demand by employing energy storage,
An alternative that makes use of stored thermal energy is described in the link below, from the journal Sustainability. In addition to being much less expensive than the choices described in the FERC report it would also greatly reduce the transmission costs because it uses energy sources that surround all of our buildings.
The use of solar PV is not inevitable at all. In most developed countries the predominant use for energy is for thermal applications that need not rely on electricity. If those thermal needs are met by using local thermal energy sources instead of relying on electricity and natural gas, and we employ thermal storage to flatten the loads for both heating/cooling and electricity then the need for meeting peak power demands is greatly reduced. The basic assumption that we must generate enough electricity to meet the existing peak electricity loads is not valid.
There are two distinctly different reasons for wanting to store energy: to provide backup or to match the energy supply with the demand. For the former you can use batteries but for the latter application you can use much less expensive approaches like exergy storage, which uses electricity for its input but delivers demand reduction for its output. Both approaches deliver the same results if you are struggling to match supply and demand on a power grid. It would be useful if articles on electricity storage kept these differing objectives separate.
Three of the four 'building blocks' are counter-productive:
1) Make fossil fuel plants more efficient
2) Dispatch low-emissions sources, namely natural gas, more often
4) Expand use of energy efficiency
They propose that we should continue to rely on the use of fossil fuels instead of replacing such fuels with alternatives that do not produce GHG's. The EPA is proposing that we should protract the fossil fuel era, which is the opposite of what we really need to do - replace such fuels with the abundantly available non-GHG-emitting alternatives.
REW is doing us all a disservice by referring to carbon as the culprit. Carbon is not poisonous and it is not a greenhouse gas. We certainly DO need to stop polluting the atmosphere by burning coal but curbing pollution and curbing GHG's are separate issues so REW should take care to treat them separately.
The same goals can be met if you employ energy storage in general instead of assuming the use of battery storage. We use energy in two forms: electricity and thermal, and in most places the thermal form dominates. Moreover, it is the thermal demand that fluctuates the most from season to season. If you store the thermal energy in thermal form then you do not need to keep converting the energy back and forth between the two forms, which entails losses. While you might still want to use batteries for the part of the energy that is used in electrical form the size of the batteries can be reduced by a couple of orders of magnitude so they are more cost effective. The fluctuations in the electrical component are short term (daily) variations rather than long term (seasonal) variations so the required storage capacity is small.
The rate of solar insolation in the UK is less than 120 W/sq. m and the country is legendary for its long gaps between sunny periods. That does not imply that solar energy is useless in the UK but it does suggest that its role should be niche applications that take advantage of the potential to store solar thermal energy.
Neil: I assume that you have dropped a few zeroes in citing 4 kWh/year as your output. A solar thermal collector (with storage) for a house would be only one quarter the size of a PV collector and in spite of that small size the storage system would deliver about five times as much energy. Most of that energy would be extracted from the air, but air-source systems have difficulty delivering the temperature that is needed for DHW and in handling peak demands. The solar input fixes both problems. Homes that use such systems burn no fuels at all and they reduce the peak demands for electricity. A given reduction in peak demand is more useful than the equivalent amount of power generation because it does not have to be transmitted.