Elon Musk and big ideas go together. But the question is: should Tesla, Inc. (NASDAQ: TSLA) and going private be similarly paired? That's the idea behind Musk's recent early-morning tweet on August 7, 2018, in which he wrote, "Am considering taking Tesla private at $420. Funding secured."

Going private would reduce Tesla's regulatory and reporting requirements. Doing so would also allow the company to focus more on its longer-term plans and strategic direction. (For more, see: What if Tesla Goes Private?)

Moreover, by not being subject to reporting its earnings on a regular basis, Tesla would not be distracted by having to meet investors' quarterly expectations and would not have to worry about wild swings in its share price rattling investor confidence. Investors drove Tesla's share price up nearly 11% on the day Musk published his tweet, showing broad market support for his latest big idea.

Investors who want a cost-effective way to gain exposure to Tesla should consider investing in one of these three exchange-traded funds (ETFs) that include the California-based electric car company as a major holding. (See also: Tesla: 6 Secrets You Didn't Know.)

VanEck Vectors Global Alt Energy ETF (NYSEARCA: GEX)

Launched in 2007, the VanEck Vectors Global Alt Energy ETF seeks to provide similar returns to the Ardour Global Index. The fund achieves this by investing a minimum of 80% of its assets in small- and mid-capitalization companies that operate primarily in the alternative energy space and generate 50% of their revenue from the industry. Tesla, the fund's top-weighted allocation, accounts for 11.48% of its portfolio, giving investors ample exposure the electric car maker. Other top holdings in the fund include Eaton Corporation PLC (NYSE: ETN) at 9.99% and Vestas Wind Systems A/S (OTC: VWDRY) at 9.5%.

The VanEck Vectors Global Alt Energy ETF charges investors an annual management fee of 0.63% and has $89.84 million in net assets. As of August 2018, GEX has a five-year annualized return of 5.14% and a three-year annualized return of 4.7%. Year to date (YTD), it has returned 1.29%. The fund also pays a 1.24% dividend yield. (See also: The Top Tesla Shareholders.)

ARK Industrial Innovation ETF (NYSEARCA: ARKQ)

The ARK Industrial Innovation ETF, formed in September 2009, invests in companies that are likely to benefit from automation or other forms of technological innovation and advancements. Although the fund invests in both domestic and foreign securities, the bulk of its exposure (74.79%) targets U.S. companies. China commands the largest share of foreign exposure at 11.74%. Tesla is the fund's top allocation at 11.44%. Stratasys Ltd. (NASDAQ: SSYS) and Baidu, Inc. (NASDAQ: BIDU) round out the ETF's top three holdings.

The ARK Industrial Innovation ETF has assets under management (AUM) of $151.95 million. Its expense ratio of 0.75% is higher than the 0.55% category average, but the fund's outstanding performance warrants its higher management fees. As of August 2018, ARKQ has three- and one-year annualized returns of 25.47% and 26.1%, respectively. The fund's YTD returns of 11.87% also look impressive when compared with the broader market – the Standard and Poor's 500 Index (S&P 500) has returned 5.97% over the same period. (See also: Tesla Breaks Out as Elon Musk Taunts Short Sellers.)

First Trust NASDAQ Clean Edge Green Energy ETF (NASDAQ: QCLN)

The First Trust NASDAQ Clean Edge Green Energy ETF's primary objective is to track the NASDAQ Clean Edge Green Energy Index. The fund, created in 2007, achieves this by investing the majority of its assets in securities that make up the underlying index. This includes U.S.-listed companies that manufacture, develop and install clean-energy technologies. QCLN holds 26,772 Tesla shares, which accounts for 10.13% of its portfolio. The ETF's other significant holdings include Albemarle Corporation (NYSE: ALB) with an 8.23% weighting, ON Semiconductor Corporation (NASDAQ: ON) with a 6.95% weighting and Hexcel Corporation (NYSE: HXL) with a 6% weighting.

The First Trust NASDAQ Clean Edge Green Energy ETF charges investors an annual management fee of 0.6%; however, the fund's 0.56% dividend yield mostly offsets this expense. It has $94.88 million in AUM. Although the fund has a modest 1.62% YTD return as of August 2018, its 9.5% return over the past three years and 9.63% return over the past 12 months have energized investors. (See also: If You Had Invested Right After Tesla's IPO.)