Solution 2: using ocean-based pipes to promote algae growth
Solution 3: going solar (below)
Scientific American recently announced a grand solar-power plan that would “generate 100 percent of all US electricity and more that 90 percent of total US energy ” by 2100 at a cost of about $10 billion a year for 40 years. Here is their synopsis:
A massive switch from coal, oil, natural gas and nuclear power plants to solar power plants could supply 69 percent of the U.S.’s electricity and 35 percent of its total energy by 2050.
A vast area of photovoltaic cells would have to be erected in the Southwest. Excess daytime energy would be stored as compressed air in underground caverns to be tapped during nighttime hours.
Large solar concentrator power plants would be built as well.
A new direct-current power transmission backbone would deliver solar electricity across the country.
You can read the details of the plan here.
What about the cost?
Although $420 billion is substantial, the annual expense would be less than the current U.S. Farm Price Support program. It is also less than the tax subsidies that have been levied to build the country’s high-speed telecommunications infrastructure over the past 35 years. And it frees the U.S. from policy and budget issues driven by international energy conflicts.
Without subsidies, the solar grand plan is impossible. Other countries have reached similar conclusions: Japan is already building a large, subsidized solar infrastructure, and Germany has embarked on a nationwide program. Although the investment is high, it is important to remember that the energy source, sunlight, is free. There are no annual fuel or pollution-control costs like those for coal, oil or nuclear power, and only a slight cost for natural gas in compressed-air systems, although hydrogen or biofuels could displace that, too. When fuel savings are factored in, the cost of solar would be a bargain in coming decades. Link.
Recent news about solar energy developments can be found here.