Just by eyeballing the graph you can get an idea of the price range of gas and coal. If we assume (back-of-envelope-style):

The graph shows a range of electricity price using gas of 5 - 7.5 cents/kWh.

1m² of natural gas (methane) contains ~10kWh of energy and the power plant is 40% efficient, so 1m² gives 4kWh of electricity. That means the estimated price of producing electricity by gas is 20-30cents/m² of gas. Note that this is the cost to the power plant operator per m² consumed, which means the price of gas + running costs.

A quick googling shows that the price of Russian
 gas in Dec. 2009 was ~23cents/m² .

I don't know if the gas fired power plant efficiency is realistic but if you use the expected price increase from $30/ton CO₂ you get a figure for the efficiency about 40% (but the error bars are too big to fit into the comment box).

For coal the price range is 7-9cents/kWh. High-quality coal contains ~9kWh/kg. Again with 40% efficiency that translates into 2.5-3.2cents per kg of coal ($25-32/ton), again neglecting non-fuel costs in production.

Real capricorns don't believe in astrology.