Category Archives: Sci / Tech

ELECTRICITY GENERATION

The share of generation fueled by coal in the US has declined dramatically in recent months.Coal’s share of total power generation first fell below 40 percent in November last year and averaged 36 percent during the first quarter of 2012,compared with an average of almost 45 percent during the same period last year.

Much of this reduction has resulted from the decreased utilisation of exciting coal-fired capacity,including some capacity that is scheduled to be retired during the next few years.

The reduction in coal generation has been offset by increased utilisation of natural gas combined cycle plants.EIA expects that the higher natural gas costs projected later in 2012 and in 2013,along with record coal stocks,will encourage generators to increase their utilisation of coal-fired power plants next year.

After a projected decline of 13 percent in 2012,EIA forecasts total generation by coal across all sectors to rise by 3 percent in 2013.

In contrast,total generation by natural gas is forecast to rise 22 percent this year and then rise by less then 1 percent in 2013.

Tata Power to buy BP’s stake in Tata BP solar

Tata Power Company Limited has signed a deal with BP alternative energy holdings to acquire the latter’s 51percent stake and preference shares in Tata BP Solar India Private Limited.Following the acquisition, Tata Power would own 100percent stake in Tata BP Solar.The former would have access to certain BP technologies till 2013 and an agreement  for this is expected to be signed soon. The stake slae by BP is in line with its decision to exist the solar power business over the next few months.Tata BP solar was incorporated in 1989 as a joint venture between UK based BP solar and Tata Power  to execute solar power projects.

Global System for Mobile Communication

1.It is TDMA(time division multiple access) FDMA(frequency division multiple access)technology.

2.The initial coverage area for each cell is greatly offered by link budget.(how much loss(db)can be tolerated over the air link between the phone & base station).

3.It is having hard hand off.(break before make).

4.It cover less cell radius.

5.GSM claim 3/9 reuse pattern(theree sector base station)frequency reuse equal 9)with the use frequency hopping,it only reduces the variance of C,I doesn’t improve C/I).

6.It is more expansive.

7.GSM suffers form the band width (B.W) limitation imposed by TDMA design.(time division multiple access).